U2 just launched a major tour celebrating the 30th anniversary of their iconic album The Joshua Tree and "Mothers of the Disappeared" is one of the deeper album cuts that rarely makes their hits filled performances. So adding to the anticipation of the track, the band welcomed not only Eddie Vedder but Mumford and Sons to join in on the song.

After the first verse, Bono calls out, "Where is Eddie Vedder? Spirit of Seattle, spirit of Chicago, spirit of America. Where is Eddie?" as the singer walked out to the delight of the crowd. After an embrace with Bono, Vedder stepped up to the mic and took a verse of the song. Upping the ante, Bono then asked for Mumford and Sons, who joined in on the "ohs" of the track.

U2 are set to hit Santa Clara and Los Angeles this week. Dates of their tour and ticketing details can be found here. Meanwhile, Vedder is set to join his Pearl Jam bandmates as they start a European tour leg on May 27 in Amsterdam. Dates for Pearl Jam's touring can be found here.